Anode active material including carbon composite for lithium secondary battery and method of manufacturing the same

Abstract

An anode active material contains a carbon composite, and the carbon composite may include a core particle including hard carbon and a skin layer placed on a surface of the core particle. The skin layer includes graphite particles attached to the surface of the core particle at a predetermined angle with respect to the surface and the graphite particles include graphite-based carbon material. The skin layer further includes an amorphous carbon layer filling a space between the graphite particles and attaching the graphite particles to the surface of the core particle. The carbon composite has a ratio of I D to I G in a range of 0.8 to 1.5 (0.8≤I D /I G ≤1.5) in Raman analysis where I D is the intensity of D peak at 1300 cm −1 to 1400 cm −1 and I G is the intensity of G peak at 1500 cm −1 to 1600 cm −1 .

What is claimed is: 
     
       1. An anode active material comprising a carbon composite, the carbon composite comprising:
 a core particle including hard carbon; and 
 a skin layer placed on a surface of the core particle, 
 wherein the skin layer comprises 
 graphite particles attached to the surface of the core particle at a predetermined angle with respect to the surface and including graphite-based carbon material; and 
 an amorphous carbon layer filling a space between the graphite particles and attaching the graphite particles to the surface of the core particle, 
 the carbon composite has a ratio of I D  to I G  in a range of 0.8 to 1.5 (0.8≤I D /I G ≤1.5) in Raman analysis where I D  is the intensity of D peak at 1300 cm −1  to 1400 cm −1  and I G  is the intensity of G peak at 1500 cm −1  to 1600 cm −1 , and 
 50% by weight or more of the graphite particles based on the total weight of the graphite particles are attached at an angle of 20° to 90° with respect to the surface of the core particle. 
 
     
     
       2. The anode active material of  claim 1 , wherein the graphite particles are in direct contact with the surface of the core particle. 
     
     
       3. The anode active material of  claim 2 , wherein the carbon composite exhibits a surface morphology that is not smooth by the graphite particles. 
     
     
       4. The anode active material of  claim 1 , wherein based on the weight of the carbon composite, the core particle is included in 30% by weight to 50% by weight, the graphite particles are included in 40% by weight to 60% by weight, and the amorphous carbon layer is included in 10% by weight to 30% by weight. 
     
     
       5. The anode active material of  claim 1 , wherein the carbon composite has a particle diameter having a median value (D0.5) of about 10 μm to about 30 μm. 
     
     
       6. An anode active material comprising a carbon composite, the carbon composite comprising:
 a core particle including hard carbon; 
 a skin layer placed on a surface of the core particle, 
 wherein the skin layer comprises 
 graphite particles attached to the surface of the core particle and including graphite-based carbon material; and 
 an amorphous carbon layer filling a space between the graphite particles and attaching the graphite particles to the surface of the core particle, 
 the carbon composite has a ratio of I D  to I G  in a range of 0.8 to 1.5 (0.8≤I D /I G ≤1.5) in Raman analysis where I D  is the intensity of D peak at 1300 cm −1  to 1400 cm −1  and I G  is the intensity of G peak at 1500 cm −1  to 1600 cm −1 , 
 50% by weight or more of the graphite particles based on the total weight of the graphite particles are attached at an angle of about 20° to about 90° with respect to the surface of the core particle, and 
 the graphite particles are in direct contact with the surface of the core particle. 
 
     
     
       7. The anode active material of  claim 6 , wherein the carbon composite exhibits a surface morphology that is not smooth by the graphite particles. 
     
     
       8. The anode active material of  claim 6 , wherein based on the weight of the carbon composite, the core particle is included in 30% by weight to 50% by weight, the graphite particles are included in 40% by weight to 60% by weight, and the amorphous carbon layer is included in 10% by weight to 30% by weight. 
     
     
       9. The anode active material of  claim 6 , wherein the carbon composite has a particle diameter having a median value (D0.5) of about 10 μm to about 30 μm. 
     
     
       10. The anode active material of  claim 6 , wherein the carbon composite has a BET specific surface area of about 2 m 2 /g to about 8 m 2 /g.